Background Inflammation linked to diabetic kidney disease (DKD) may affect white blood cell (WBC) counts and differentials. We examined the cross-sectional associations of total WBC count and WBC fractions with structural lesions of DKD in 108 Pima Indians with Type 2 diabetes who underwent research kidney biopsies. We also examined the longitudinal association of these WBC variables with renal function loss (RFL) in 941 Europeans with Type 2 diabetes from the SURDIAGENE study. Methods Associations of WBC variables with morphometric parameters were assessed by linear regression. RFL was defined as≥40% loss of estimated glomerular filtration rate from baseline. Associations with RFL were evaluated by Cox regression. Hazard ratios (HRs) were reported per standard deviation increment of each WBC variable. Results After multivariable adjustment, lymphocyte (r = -0.20, P = 0.043) and eosinophil (r = 0.21, P = 0.032) fractions in the Pima Indians correlated with glomerular basement membrane width. Eosinophil fraction also correlated with glomerular filtration surface density (r = -0.21, P = 0.031). Lymphocyte fraction (r = 0.25, P = 0.013), neutrophil fraction (r = -0.23, P = 0.021) and the neutrophil:lymphocyte ratio (r = -0.22, P = 0.024) correlated with percentage of normally fenestrated endothelial cells. During median follow-up of 4.5 years, 321 SURDIAGENE participants developed RFL. Lower lymphocyte fraction [HR = 0.67, 95% confidence interval (95% CI) 0.60-0.76] and higher neutrophil fraction (HR = 1.35, 95% CI 1.20-1.52), total WBC count (HR = 1.20, 95% CI 1.08-1.35) and neutrophil:lymphocyte ratio (HR = 1.44, 95% CI 1.28-1.62) each predicted RFL in this cohort. Conclusions WBC fractions associate with morphometric lesions of DKD and predict RFL in individuals with Type 2 diabetes.
Bibliographical noteFunding Information:
This research was sponsored by the Intramural Research Program of the National Institute of Diabetes and Digestive and Kidney Diseases and by the American Diabetes Association [Clinical Science Award (1-08-CR-42)]. The SURDIAGENE study was supported by grants from PHRC-Poitiers 2004 and AFD (Research Grant 2003) and by the Groupe d’Etude des Maladies Métaboliques et Systémiques (Poitiers, France).
- diabetic kidney disease
- kidney biopsy